Good info you had JUST said it was not the relay board you never said you had just replaced it!
Ok so to run a diagnostics to see if it has any hidden error codes .
To Enter Diagnostics Mode:
Before proceeding with any corrective action, perform the following steps to enter the Diagnostics mode.
1. To recall last failure code, if not displayed, press the OFF key to place the range in an idle state.
2. Press the OFF and START keys in the following order: OFF, OFF, START.
3. Verify the error code displayed on the control by observing for longer than 1 minute. If the error returns, use the applicable procedure listed below for the actual error code that is displayed.
And tell me what if any F error codes you are seeing .
You only have four components that make this unit heat . Which are the Display Control Board /Clock . the Main Relay Board /Appliance Manager , the Temp Sensor/Probe and the Heating Element.
And if the Display is still showing the set temperature when the Relay Board shuts the voltage off to the Element then it is not the Display Control Board.
If you have ohmed the Temp Senor/Probe out and get 1,100 ohms the Sensor is fine.
If the Element heats when it does get voltage , then it is not the Heating Element.
Which means it has to be internal of the Control Board!
Unless your not giving me the correct information .
So let`s run a diagnostics mode and see what error codes show up .
They can be from F0 to F6 and they will have an E number on the end ranging from E0 all the way to E5